Method of piercing holes in sanding discs

ABSTRACT

A sanding tool having a power driven circular backing structure or carrier for driving a circular sanding disc, with the backing structure containing openings through which air and abraded particles can be drawn by suction from a work surface to a collection location, and with a piercing tool being provided and adapted to be positioned opposite the backing structure in a predetermined located relation with respect thereto and to pierce apertures in the sanding disc communicating with the openings in the backing structure.

Unite til States Patent Hutchins 1 Oct. 15, 1974 i 1 METHOD OF PIERCINGHOLES IN 2,160.374 5/1939 Vciliclit? 29/432 x SANDHNG DISCS 2,856.680lO/l958 Johnson ct al..... 1. 29/432 3,205,112 9 1965 Gilbert i. 156 253i 1 Inventor: Alma Hutchms, 49 Lotus 3,638,362 1/1912 $1611 51/273 xAve., Pasadena, Calif. 91107 22 dI l 16 1973 Primary Examiner-Charlie T.Moon 1 l 6 y Attorney, Agent, or FirmWilliam P. Green [21] Appl. No:379,437

Related US. Application Data ABSTRACT [62] Division f 5 282,343, Aug 21,1972 A sanding tool having a power driven circular backing structure orcarrier for driving a circular sanding disc, 52] 0.5.01 29/445, 29/1635,156/253 with the backing structure containing p ning [51] int. Cl B23p9/00 through which air and abraded Particles can be draw" 58 Field ofSearch 29/432, 445, 163.5; y Suction from a work surface to a Collection1099- 51/170 R, 270, 273, 275; 93/11, 1 A 1 D 1 tion, and with apiercing tool being provided and 13; 156/253 adapted to be positionedopposite the backing structure in a predetermined located relation withrespect [56] R f r n e Cit d thereto and to pierce apertures in thesanding disc communicating the openings in thfi 1,800,341 4/1931 Davies51/170 R structure 2.115543 4/1938 Thackray.... .1 156/253 x 3 Claims, 9Drawing Figures 21 A i i i 1 METHOD OF PIERCING HOLES IN SANDING DISCSCROSS REFERENCE TORELATED APPLICATION This is a division of applicationSer. No. 282,348, filed Aug. 21, 1972.

Certain features of the apparatus and methods of the present applicationhave been disclosed and claimed in my copending applications Ser. No.213,018 filed Dec. 28, 1971, now US. Pat. No. 3,785,092, on AbradingTool Having Suction System for Collecting Abraded Particles, and Ser.No. 282,155, filed Aug. 21, 1972, now US. Pat. No. 3,788,011, onPiercing of Air Suction Holes in Abrasive Sheet Materia BACKGROUND OFTHE INVENTION This invention relates to portable power driven tools forabrading a work surface, such as for example powered sanding tools orthe like.

My copending application Ser. No. 213,018, now US. Pat. No. 3,785,092,discloses certain unique sander type tools in which an air suctionsystem is provided for drawing air and abraded particles from the worksurface being treated, and delivering those particles to a collectionbag, in order to prevent escape of the produced dust into theatmosphere. Preferably, the power driven carrier or backing structure ofthe tool which carries and drives the sandpaper or other abrasive sheetmaterial is formed to contain openings through which some of the suctionair is drawn, with the abrasive sheet itself also desirably containingsuction openings registering with those in the power driven structure.

The second of my above mentioned applications, Ser. No. 282,155,discloses apparatus and methods for forming such air suction aperturesin a sheet of abrasive material, by means of a piercing tool which canbe aligned with the power driven element which carries the abrasivesheet and will form the desired apertures after application of theabrasive sheet to that power driven element and in accurate registrywith the apertures in the power driven element itself. The particularpiercing tool there disclosed is best adapted for forming apertures inan abrasive sheet carried by a rectangular type sanding shoe, which maybe driven either reciprocally along a straight line, or orbitally.

SUMMARY OF INVENTION The present. invention relates to the provision ofadditional piercing apparatus and methods, which fall within the scopeof the broad generic invention of my above discussed prior applicationSer. No. 213,018, but which also incorporate certain additional featuresnot disclosed in my prior application, and particularly adapting thepresent apparatus for piercing holes in circular type abrasive sheets.As will appear, the piercing tool and a sander carrying such an abrasivedisc may have coacting locating means adapted to interengage in arelation effectively positioning the piercing tool directly opposite acircular backing structure carrying the disc in precisely the rightorientation for producing properly located apertures in the abrasivedisc upon actuation of the piercing tool. The latter preferably has anumber of projections arranged in a pattern corresponding to the patternof apertures in the circular backing structure, and the locating meanswhen properly engaged will position these apertures directly axiallyopposite the openings in the backing structure, so that when theprojections and backing structure are relatively moved toward oneanother the projections will pierce the desired apertures in theabrasive disc at precisely the locations of the openings in the backingstructure.

The locating means may include an element or elements projecting fromthe piercing tool and engageable with coacting means preferably formedon the periphery of the circular backing structure. More particularly,the backing structure may contain a number of circularly spaced notches,into which locating elements carried by the piercing tool are receivedina proper relative orientation of the parts. Also, to maximize theversatility of the apparatus, the locating elements or means may beadjustable generally radially relative to the remainder of the piercingtool, in a manner enabling adjustment of the tool to fit and coact withbacking elements of two or more different sizes.

BRIEF DESCRIPTION OF THE DRAWING The above and other features andobjects of the invention will be better understood from the followingdetailed description of the typical dembodiment illustrated in theaccompanying drawings, in which:

FIG. 1 is a side view of a sanding tool embodying the invention, withthe tool partially broken away to illustrate its interior parts;

FIG. 2 is an enlarged bottom view taken on line 2-2 of FIG. 1;

FIG. 3 is an explodedperspective view showing the circular backingstructure of the sanding tool, and showing also the piercing tool;

FIG. 4 is a view of the piercing tool and the backing structureof thesander taken on line 4-4 of FIG. 3;

FIG. 5 is partially sectional and partially elevational view taken online 5-5 of FIG. 4;

FIGS. 6 and 7 are sections taken on lines 6--6 and 77 of FIG. v5;

FIG; 8 is a fragmentary view taken on line 88 of FIG. 5; and

FIG. 9 corresponds to a portion of FIG. 5, with the piercing toolshownin its fully interfitting piercing engagement with the sander.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. '1 shows a powered portablesanding tool 10 having a handle body 11 by which the tool is manipulatedto perform a sanding operation on a typically horizontal work surfacerepresentd a.t12.The sandpaper carrying and backing unit 13 of the toolis essentially circular (see FIG. 2), and is driven by a motor 14contained within handle body 11. Backing unit 13 may be driven eitherorbitally about the motor axis 16, or rotativelY about that axis, withthe former type drive being typically illustrated in FIG. 1. Morespecifically, in the illustrated arrangement, the driven shaft 15 of themotor is power rotated about the vertical axis 16, and has an eccentricportion 17 turning about an axis 18 parallel to but offset from axis 16This eccentric portion 17 of shaft 15 is connected to and drives theinner race of a ball bearing assembly 19', whose outer race is connectedto and drives a head 120, which therefore oscillates orbitally aboutaxis 16 upon energization of the motor. Portion 17 of the shaft may alsocarry and drive a counterweight 117 shaped to counterbalance theeccentricity of the unit 13 and its mounting parts.

Unit 13 includes a circular rigid backing plate 20, to the front ofwhich there is cemented or otherwise mounted a circular cushion 21formed of rubber or other preferably elastomeric material, with both ofthese elements being centered about the orbiting axis 18, and with theunit 13 being rigidly connected to and driven by element 20 through anexternally threaded stud or screw 22 which projects rearwardly fromplate 20 along axis 18 and is rigidly attached thereto. The undersurface23 of cushion 21 lies generally within a plane disposed transversely ofaxis 18, though this front face 23 may have small irregularities (notshown). Against the front face 23 of cushion 21, there is provided acircular disc of sandpaper or other abrasive ma terial 24, also centeredabout axis 18, and which may be detachably secured to the cushion in anyconvenient manner, as by an appropriate pressure sensitive adhesivesubstance.

The body 11 of the tool may carry a preferably circular and preferablyslightly deformable shroud 25, secured to and projecting downwardly froma cylindrical skirt 26 attached to body 11, to provide an enclosurewithin which a suction is created for drawing abraded particles from thework surface through a tube 27 and hose 28 to a collection bag or othercollection container. This flow of air may be created in any convenientmanner, butis optimally developed by an aspirator action, produced bythe emission of a primary flow of air through an inner tube 31 of anaspirator 32 into the surrounding outer tube 27 at 32, to draw airthrough that tube 27 and to bag 29 by aspirator action. The primary flowof air in tube 31 may come from motor 14, which in the presentlypreferred form of the invention is a rotary pneumatically driven motorreceiving compressed air from a-source 33 through a hose 34, anddischarging the air still under pressure from the exhaust side of themotor through a line 30 leading into the mentioned tube 31. The rate offlow of this air is sufficiently great to draw air and abraded particlesrap idly upwardly from the work surface 12 within shroud 25 and intotube 27 for delivery with the primary air stream to bag 29.

Some of this suction air moves upwardly from the work surface through aspace 35 radially between backing unit 13 and shroud 25. Additionalsuction air moves upwardly through a series of circularly spacedapertures 36 extending axially through'both the cushion 21 and backingplate 20 of circular unit 13. To pass this air into passages 36, theabrasive sheet 24 itself contains apertures 37 which are axiallyopposite and register with openings 36.

For forming these apertures 37 in the sandpaper disc 24, I provide apiercing tool 38 (FIGS. 3 and 4), having a number of projections 39which are arranged in a pattern corresponding to the pattern of openings36 in unit 13, so that when the piercing tool is properly positionedopposite unit 13 it can pierce holes in an initially imperforate disc ofsandpaper at exactly the locations of the openings 36. Moreparticularly, as seen best in FIG. 2, the openings 36 are desirably alllocated a common distance d from the axis 18 about which the circularunit 13 is centered. Also, all of the pairs of successive openings 36are desirably spaced apart the same angular distance a, typically 60degrees as shown, to desirably provide six evenly circularly spacedopenings.

These openings may be located approximately midday between axis 18 andthe periphery of backing unit 13, and may be shaped cylindrically aboutindividual axes 140 extending parallel to axis 18.

Piercing tool 38 may include a main rigid body or plate 40, desirablyformed of a suitable rigid metal such as steel, and which is preferablyplanar, and in the position of FIGS. 3, 4, and 5 is disposedtransversely of axis 18. This plate may be circular, having a peripheralcircular edge 41 centered about axis 18 and of a diameter smaller thanthe diameter of backing unit 13. The six projections 39 are rigidlycarried by plate 40 and extend along the previously mentioned individualaxes 140, and may be all identical, having first externally cylindricalportions 42 adjacent plate 40, and pointed conically taperingextremities 43 for punching through the sandpaper. The axial lengths tof these projections 39 may correspond approximately to or be slightlygreater than the axial thickness of unit 13 at the locations of openings36. The piercing tool may be manipulated by a handle knob 44 carried atthe outer side of plate 40 and secured thereto by a screw 45 extendingthrough an opening 46 in plate 40 for threaded connection into thehandle.

The locating means for properly positioning the piercing toolpreferablyinclude two identical locating elements 47, which are mountedto plate 40 at circularly spaced locations for engagement with theperiphery of unit 13 at those two locations. Each of the locatingelements 47 may be formed of an elongated strip of flat metal or othersuitable material, which is essentially stiff and rigid to maintain theshape illustrated in the figures, but may be very slightly resilientlydeflectible during positioning of the piercing tool in engagement withunit 13. For this purpose, elements 47 may be formed of a very stiffspring steel.

As seen best in FIG. 5, each of the elements 47 has a radially extendingportion 48 located at and extending along the outer side of plate 40,and projecting from the center of plate 40 to a location 49 generallyopposite the periphery of unit 13. From this location, each element 49is bent to extend generally axially at 50, but desirably at a slghtlyoutwardly flaring angle as seen in FIG. 5, to a location 51, at whichthe extremity of element 47, is turned generally radially inwardly at 52to form a locating finger. The radially inner edge 152 of this fingermay have the rounded configuration illustrated in FIG. 8, correspondingto the shape of a series of axial grooves 53 formed in the generallyaxial cylindrical. peripheral surface 54 of cushion 21. These grooves 53are formed at equally circularly spaced locations about axis 18,desirably directly radially opposite the various corresponding openings36. The two elements 47 are so located as to properly position all ofthe projections 39 directly axially opposite corresponding openings 36of unit 13 when the two elements 47 are received in any selected pair ofthe notches 53. As seen in FIG. 4, the elements 47 are desirably spacedapart circularly a distance of i.e. a distance twice as great as thespacing between successive ones of the grooves 53 and openings 36.

Elements 47 are mounted to plate 40 for radial adjusting movementrelative to plate 40, so that fingers 52 may be properly positioned forengaging the peripheries of two or more different conventional sizes ofbacking units 13. For this purpose, the periphery of plate 40 may formtwo axially turned ears or lugs 55, containing guide openings 56 shapedto slidably receive radial portions 43 of elements 47, and to therebyguide elements 47 for only radial adjusting movement between the fullline and broken line positions of FIGS. 5 and 7. Near its innerextremity, each of the elements 47 may contain two or more radiallyspaced openings 57, dimensioned to exactlyreceive and be accuratelylocated by the shank MS of screw 45, and spaced apart to enableadjustment of element 47 by positioning of the shank of screw 45 withinwhichever of the two apertures 57 is desired. The spacing of theseapertures is predetermined to accurately locate fingers 52 at the properradii for engagement with the two or more selected known diameters ofheads 13.

To describe the manner of use of the illustrated equipment, assume thatan initially imperforate disc of sandpaper 23 has been adhered to theforward face 23 of circular backing unit 13, as illustrated im FIG. 5.The operator then grasps handle 44 of piercing tool 38 with one hand,while holding the sander with the other hand, and moves the piercingtool to the position illustrated in FIGS. 4 and 5 directly axiallyopposite unit 113 and the sandpaper. In this position, plate 40 of thepiercing tool is parallel to the sandpaper and to unit 13, and perpendicular to axis 18. The fingers 52 of the two locating elements 47are moved behind the circular peripheral edge 59 of the sandpaper disc24, which edge may project as far out as the peripheral edge surface 54of cushion 21. After the fingers 52 have been moved to this positionbehind the plane of the sandpaper disc, the piercing tool is so held asto maintain fingers 52 in contact with the periphery of the cushion 21while the operator turns the piercing tool 38 about axis 18 until hefeels the fingers 52 fall into and engage two of the notches 53. Whenthis occurs, the piercing tool is in proper orientation to locate thevarious projections 39 directly axially opposite openings 36 in thecircular unit 13, so that the operator may then merely press thepiercing tool leftwardly in FIG. 5 relative to unit 13, to punch holesin the sandpaper as shown at 37 in FIG. 1. That is, the piercing tool ismoved from the full line position of FIG. 5 to the position shown inbroken lines in that Figure, and shown fragmentarily in FIG. 9, whilemaintaining fingers 52 at the locations of the contacted grooves. Asstated previously, the positioning of the grooves and fingers is suchthat the piercing projections are properly located so long as fingers 52are received within any two of the grooves spaced '120 degrees apart.The piercing tool is then withdrawn, and the sander is placed inoperation as shown in FIG. 1 to sand the surface 12, with air beingadmitted to motor 14 by actuation of control handle 60, and with thepreviously described aspirator induced flow of suction air movingupwardly through openings 36 and 37, and through the peripheral space35, for delivery of abraded dust particles to collection bag 29.

If it is desired to utilize the piercing tool with a sander having asmaller diameter head 13, the elements 47 are adjusted to the brokenline positions of FIGS. 5 and 7 so that fingers 47 will properly engagegrooves such as those shown at 53 in the reduced size head.

While a certain specific embodiment of the present invention has beendisclosed as typical, the invention is of course not limited to thisparticular form, but rather is applicable broadly to all such variationsas fall within the scope of the appended claims.

I claim: 1. The method that comprises: attaching an essentially circularsheet of abrasive material to an essentially circular power driven backing structure of a sander which contains suction openings in the backingstructure for drawing air and abraded particles from a work surface,

positioning opposite said backing structure and carried abrasive sheet apiercing tool having projections arranged in a pattern corresponding tothe pattern of said openings in the backing structure, and with thepiercing tool turned about the center of said essentially circularbacking structure and abrasive sheet to a position in which saidprojections are directly opposite said openings in the backingstructure, and

moving said piercing tool and said backing structure relatively axiallytoward one another to pierce holes in the abrasive sheet by saidprojections at the locations of said openings in the backing structure.

2. The method as recited in claim 1, including locating said piercingtool relative to said backing structure by moving and turning thepiercing tool to a position in which locating means on the piercing toolinterfit in predetermined locating relation with coacting locating meanson the backing structure.

3. The method as recited in claim I, in which said tool is positioned byfirst engaging locating means on said tool with the periphery of saidbacking structure, and then turning said tool relative to said backingstructure about the axis of said backing structure until said locatingmeans interfit with coacting locating means on said periphery of thebacking structure.

1. The method that comprises: attaching an essentially circular sheet ofabrasive material to an essentially circular power driven backingstructure of a sander which contains suction openings in the backingstructure for drawing air and abraded particles from a work surface,positioning opposite said backing structure and carried abrasive sheet apiercing tool having projections arranged in a pattern corresponding tothe pattern of said openings in the backing structure, and with thepiercing tool turned about the center of said essentially circularbacking structure and abrasive sheet to a position in which saidprojections are directly opposite said openings in the backingstructure, and moving said piercing tool and said backing structurerelatively axially toward one another to pierce holes in the abrasivesheet by said projections at the locations of said openings in thebacking structure.
 2. The method as recited in claim 1, includinglocating said piercing tool relative to said backing structure by movingand turning the piercing tool to a position in which locating means onthe piercing tool interfit in predetermined locating relation withcoacting locating means on the backing structure.
 3. The method asrecited in claim 1, in which said tool is positioned by first engaginglocating means on said tool with the periphery of said backingstructure, and then turning said tool relative to said backing structureabout the axis of said backing structure until said locating meansinterfit with coacting locating means on said periphery of the backingstructure.